The trend in mobile communication systems goes towards high capacity mobile switching center (MSC) servers which are also scalable. A typical architecture for such a system is a blade cluster structure with a plurality of blades. Transmission lines that carry payload are terminated in media gateways and the switching of these resources is controlled by the MSC server. Furthermore, a pool of terminations is provided at the media gateway, the pool of terminations being controlled by the different blades of the MSC. In case one blade of the MSC server fails, the terminations controlled by said blade have to be released in order to make them available for other calls. In this context, the terminations controlled by a failed blade need to be released in an efficient way. One possibility to release the terminations controlled by the failed blade would be to subtract the different terminations one by one by sending a subtract command to each termination. However, this represents an unacceptable amount of signaling and recovery time. The same problem occurs when a board in the media gateway fails and when the terminations of that board need to be taken out of usage.
H.248 is for a control of elements in a multimedia gateway and is used as a control protocol between the media gateway and the media gateway controller. In this protocol a wildcard mechanism is known using two types of wildcards with termination IDs. These two wildcards are “ALL” and “CHOOSE”. The former “ALL” is used to address multiple terminations at once while the latter is used to indicate to the media gateway that it should select a termination satisfying a partially specified termination ID.
A termination for a media gateway is a logical entity which is the source and/or the sink of media and/or control streams. Each termination has a unique entity, the termination ID.
A context is an association between a number of terminations, the context describing the topology (who hears/sees whom) and the media mixing and/or switching parameters if more than two terminations are involved in the association. A context is created by adding the first termination and it is released by removing/subtracting the last termination.
There are many reasons why a group of terminations needs to be grouped in the media gateway or the media gateway controller which can be the MSC server. By way of example terminations may be grouped due to their different capabilities, type of security level, such as trusted or non-trusted domain, or any other aspect which is wanted based on a set of given rules.
A traditional way of grouping terminations is based on the wildcard mechanism, where certain parts of the termination identifiers in the H.248 protocol are used. Additionally, a priority indicator with value range from 0 to 15 is known from the H.248 protocol: the priority is used for a context in order to provide the media gateway with information about a certain precedence handling for a context. The media gateway controller can also use the priority to control autonomously the traffic precedence in the media gateway in a smooth way, e.g. during restart, when a lot of contexts must be handled simultaneously. Priority 0 is the lowest priority and a priority of 15 is the highest priority.
However, the handling is not optimized from a H.248 point of view, meaning that the grouping for terminations is not very flexible and not very scalable. In the H.248 protocol the termination identifier may be defined as a 32 bit value or a 64 bit value. Using a certain part of the termination identifier, e.g. the three least significant bits, for a certain purpose, for example for server identification, would introduce proprietary logic in both the server node and the media gateway. The H.248 protocol is also used between devices from different vendors, so that this kind of logic does not work in a multi-vendor environment.
Any change to the existing termination structure leads to backwards incompatibility and upgrade problems with older products that do not support the given termination identifier format. At present there is no efficient way to handle (subtract, move or modify) a massive set of terminations, where a priority indicator is set to a certain value or terminations of a certain service type or terminations relating to a certain type of interface, such as network internal or network external from a media gateway point of view. Additionally, it is difficult to handle a set of terminations based on the type of destination (trusted domain or non-trusted domain) or based on any other given policy function.